A spell can not physically change you, especially not something as extreme as a sex change BUT
I do recommend looking into glamouries ( spells which change other people's vision or perspective of you) but keep in mind glamouries that say they can change your hair and eye color etc are fake. Try to craft your own spell that can help you be perceived more as the gender you wish to be instead of the gender you are, or "hiding" your feminity / masculinity that you do not want to be showing. You can also try spells for better confidence and self expression.